How to alpha-beta pruning to expectiminimax
alpha-beta-prunning algorithm is using for improve performance and reject the options, which not consist the condition - or it's possible to set some factors of probability to take into consideration or not.
This algorithm work on tree structure - and if there are a lot of levels (10-20) - It allows you to eliminate paths - which will logically not be used - saving memory and computing resources.
In this particular case - for finding the minimum value it works like this:
First branch:

Go to B
Go to D - and there is 2 and 3 - so return the min 2
Go From B to E - and choose 5 - the minimal value in B points is actually 3 - so there isn't need for checking the next - cause everything below E, will be higher than D (3)

Second branch:

Go to
Go to F - and check 0 and 1
If C have 1 - than not necessary to go to G - cause 1 is the smaller.

The given sequence is a simplification - and in the case of this algorithm there are also layers - min &amp; max

Source:
https://www.javatpoint.com/ai-alpha-beta-pruning#:~:text=Key%20points%20about%20alpha%2Dbeta,values%20to%20the%20child%20nodes.

Implementation, however, is a more complex matter - unless we do copy and paste :-)
https://gist.github.com/exallium/1446104/5109388cfc21578f555dcac0ba54da680326af7b